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Email Verification API — deliverability, MX, SPF/DMARC, disposable check, keyless

https://assetfactory-jobs-x402.sigrunner.workers.dev/email/verify
● healthy data

Email verification that returns one deliverability record per address, up to 100 per call. It resolves MX and implicit-MX routing per RFC 5321, reads the sending domain SPF and DMARC posture, and flags disposable, role and free-provider addresses against a throwaway-domain corpus our loop keeps current. A typo detector suggests the likely intended address, and each result gets an A-to-F grade. Everything runs over DNS-over-HTTPS, so there is no SMTP mailbox probe and nothing to get rate-limited or blocked: keyless and safe to run at volume. Price is 0.002 USDC per address, paid per call on Base over HTTP 402. No API key and no subscription.

Category
data
Chains
base
Price
$0.0020–$0.0200 USDC

Quality grade

How grading works
B+ 86.1 / 100
Availability 40.0 / 40
Endpoint responded (HTTP 402)
Payability 20.0 / 20
  • ✓ Answers a real HTTP 402 challenge
  • ✓ Publishes a /.well-known/x402 descriptor
  • ✓ Payment address on record
  • ✓ Settlement network declared
  • ✓ Price declared
Demand 26.1 / 40
67 distinct payers, 904 USDC transfers in the last 30 days
Owner verified 0.0 / 3
Nobody has claimed this listing yet
Endpoint last checked 6 h ago. On-chain activity last read 22 h ago. Availability and on-chain demand are both re-probed daily; the grade updates automatically on the next pass. This grade sets search order and leaderboards; the readiness score below is shown for reference only.

x402 readiness

B · 86/100

Readiness is how fully this listing follows its protocol and how it behaved in our probes over 30 days. It is shown for reference and does not move it in search. Search order and leaderboards use the separate quality grade (here B+, 86.1/100), which weighs availability, payability and on-chain demand. How the two differ

Valid payment requirements 10/10 Payment requirements carry a payee, a mainnet network and a price.
Live 402 challenge 25/25 Paid endpoint answers with an HTTP 402 challenge (380 ms).
x402 version n/a x402 version not observed yet.
Signed descriptor n/a No x402 standard defines a signed descriptor.
Uptime (30 days) 13.75/15 11/12 probes succeeded over 30 days (92%).
Resource declaration 8/10 15 paid resources; 15 sampled lack a description.
Verified identity 5/10 Publisher descriptor (/.well-known/x402 or OpenAPI) on record; claim this listing to verify domain control.
Freshness + modern flags 3/5 seen within 30 days; declares x402.
Security declaration n/a Payment is the access control for an x402 resource.
Applicable criteria total 75 points, scaled to 100.
Responsiveness: Responsive (380 ms; bands ≤2.5 s, ≤5 s, ≤8 s, slower; penalty only).
Payment evidence: x402_challenge — We sent a request and got a live HTTP 402 challenge. Also: x402_manifest. Qualifies the payment claim; adds no points.
Measured 2026-11-11.
Nine criteria, the same as the A2A readiness score, read from our daily probe of the paid endpoint, its payment requirements and 30-day probe history. Signed descriptor and security declaration are n/a for x402 (payment is the access control), as is an x402 version we have not observed; the remaining points are scaled to 100. Grades: A>=90, B>=75, C>=60, D>=40, F<40. Display only: search order uses the quality grade.

Compared with peers

Against 10,060 reachable x402 APIs in our daily snapshot (2026-11-12 01:39 UTC). Display only; it does not change search order.

Readiness
Higher than 74% of peers
This listing 86 · peer median 78
Latency
Faster than 29% of peers
This listing 380 ms · peer median 205 ms

Where it loses the most points, and how to win them back

  • Verified identity −5 — Claim the listing and prove control of its domain.
    Now: Publisher descriptor (/.well-known/x402 or OpenAPI) on record; claim this listing to verify domain control.
  • Resource declaration −2 — Declare each paid resource with its input and output schema.
    Now: 15 paid resources; 15 sampled lack a description.
  • Freshness + modern flags −2 — Keep the listing current in the registry or source it comes from.
    Now: seen within 30 days; declares x402.

How many agent tools actually work · All statistics

Paid endpoints

15 resource(s) advertised by this origin. Each price below is that resource's own x402 price; the headline price is the range across them.

GET https://assetfactory-jobs-x402.sigrunner.workers.dev/web/extract $0.0030 / call
GET https://assetfactory-jobs-x402.sigrunner.workers.dev/web/monitor $0.0030 / call
GET https://assetfactory-jobs-x402.sigrunner.workers.dev/web/sitemap $0.0030 / call
GET https://assetfactory-jobs-x402.sigrunner.workers.dev/web/crawl $0.0040 / call
GET https://assetfactory-jobs-x402.sigrunner.workers.dev/records/changes $0.0200 / call
GET https://assetfactory-jobs-x402.sigrunner.workers.dev/records/insider $0.0200 / call
GET https://assetfactory-jobs-x402.sigrunner.workers.dev/records/exploits $0.0200 / call
GET https://assetfactory-jobs-x402.sigrunner.workers.dev/records/epss $0.0200 / call
GET https://assetfactory-jobs-x402.sigrunner.workers.dev/pools/new $0.0200 / call
GET https://assetfactory-jobs-x402.sigrunner.workers.dev/pools/draining $0.0080 / call
GET https://assetfactory-jobs-x402.sigrunner.workers.dev/jobs/search $0.0040 / call
GET https://assetfactory-jobs-x402.sigrunner.workers.dev/hiring/signal $0.0030 / call
GET https://assetfactory-jobs-x402.sigrunner.workers.dev/jobs/comp $0.0100 / call
GET https://assetfactory-jobs-x402.sigrunner.workers.dev/company/enrich $0.0100 / call
GET https://assetfactory-jobs-x402.sigrunner.workers.dev/email/verify $0.0020 / call

How to call

cURL · x402-fetch / x402-axios will auto-handle 402
curl -sS -i -X GET https://assetfactory-jobs-x402.sigrunner.workers.dev/email/verify  # expect HTTP 402 Payment Required (about 0.002 USDC/call)
/.well-known/x402.json
https://assetfactory-jobs-x402.sigrunner.workers.dev/.well-known/x402

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submission since 2026-10-30